Thermal-metabolic relationships in hatchling snapping turtles during simulated seasonal cooling

Abstract

There is limited information available regarding metabolic rates (MR) in many species or life stages of turtles. I measured MR (as O₂ consumption) in fasted hatchling snapping turtles (Chelydra serpentina) at 5–25 °C. The relationships between temperature and MR (per capita and per gram wet body mass) were exponential and linearized by Log₁₀ transformations. The relative change in MR over a 10 °C range (Q₁₀) varied with the ranges of temperatures compared and ranged from Q_{10, 15 to 5} = 3.6 to Q_{10, 25 to 15} = 9.6 to 9.9, for per capita and per gram values, respectively. The high Q₁₀ values observed here demonstrate reductions in metabolic activity with declining temperatures that typically exceeded predicted values. Such a strong thermal dependence of MR suggests a rapid response to seasonal changes, facilitating energy conservation during cooling periods and growth during warmer periods in this temperate reptile.